Glass-reinforced plastic pipe is generally prepared by spirally winding a glass fabric which has been resin-impregnated around a mandrel and thereafter curing the resin prior to removing the mandrel. Suitable resins for such pipe are polyester resins, epoxy resins, etc.
Though such pipe of commerce has distinct advantages over concrete or iron pipe, it suffers of an inherent weakness, to wit: areas of the glass fabric may not be completely saturated with resin. Thus, the glass is subject to attack by corrosive material by wicking of the corrosive materials, e.g., alkali, acids, etc., into the glass backing at points where the backing is not fully coated with resin.
Attempts have been made to alleviate this problem by lining the pipe with an inert material, e.g., polyolefin film. These attempts have met with marginal success since the polyolefins do not themselves bond to the resin used to manufacture the pipe.